Ray Optics and Optical Instruments — Physics STD 12 Science — Question

Define potential difference and write its unit.

A cube of iron (density = 8000kg m^-3, specific heat capacity = 470J kg^-1 K^-1) is heated to a high temperature and is placed on a large block of ice at 0°C. The cube melts the ice below it, displaces the water and sinks. In the final equilibrium position, its upper surface just goes inside the ice. Calculate the initial temperature of the cube. Neglect any loss of heat outside the ice and the cube. The density of ice = 900kg m^-3 and the latent heat of fusion of ice = 3.36 × 10⁵J kg^-1.

What is the specialty of sunglasses made from polaroid instead of ordinary glass?

Answer carefully:
What meaning would you give to the capacitance of a single conductor?

If an electric current flows through a long copper wire, then what is the magnetic field inside the tube?

A proton and an electron have same kinetic energy. Which one has greater de-Broglie wavelength and why?

Will a current loop placed in a magnetic field always experience a zero force?

In a calorimeter, the heat given by the hot object is assumed to be equal to the heat taken by the cold object. Does it mean that heat of the two objects taken together remaina constant?